@spec clear(t()) :: t() | {:error, String.t()}

Clears the algorithm state

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Python prototype (for reference only):

clear() -> None

@spec computeSignature(t(), Evision.Mat.maybe_mat_in()) ::
  Evision.Mat.t() | {:error, String.t()}

Computes signature of given image.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

• image: Evision.Mat.t().

  Input image of CV_8U type.

Return

• signature: Evision.Mat.t().

  Output computed signature.

Python prototype (for reference only):

computeSignature(image[, signature]) -> signature

@spec computeSignature(t(), Evision.Mat.maybe_mat_in(), [{atom(), term()}, ...] | nil) ::
  Evision.Mat.t() | {:error, String.t()}

Computes signature of given image.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

• image: Evision.Mat.t().

  Input image of CV_8U type.

Return

• signature: Evision.Mat.t().

  Output computed signature.

Python prototype (for reference only):

computeSignature(image[, signature]) -> signature

@spec computeSignatures(t(), [Evision.Mat.maybe_mat_in()], [
  Evision.Mat.maybe_mat_in()
]) ::
  t() | {:error, String.t()}

Computes signatures for multiple images in parallel.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

• images: [Evision.Mat].

  Vector of input images of CV_8U type.

• signatures: [Evision.Mat].

  Vector of computed signatures.

Python prototype (for reference only):

computeSignatures(images, signatures) -> None

@spec create() :: t() | {:error, String.t()}

Creates PCTSignatures algorithm using sample and seed count. It generates its own sets of sampling points and clusterization seed indexes.

Keyword Arguments

• initSampleCount: int.

  Number of points used for image sampling.

• initSeedCount: int.

  Number of initial clusterization seeds. Must be lower or equal to initSampleCount

• pointDistribution: int.

  Distribution of generated points. Default: UNIFORM. Available: UNIFORM, REGULAR, NORMAL.

Return

• retval: PCTSignatures

@return Created algorithm.

Python prototype (for reference only):

create([, initSampleCount[, initSeedCount[, pointDistribution]]]) -> retval

@spec create([{atom(), term()}, ...] | nil) :: t() | {:error, String.t()}

Creates PCTSignatures algorithm using sample and seed count. It generates its own sets of sampling points and clusterization seed indexes.

Keyword Arguments

• initSampleCount: int.

  Number of points used for image sampling.

• initSeedCount: int.

  Number of initial clusterization seeds. Must be lower or equal to initSampleCount

• pointDistribution: int.

  Distribution of generated points. Default: UNIFORM. Available: UNIFORM, REGULAR, NORMAL.

Return

• retval: PCTSignatures

@return Created algorithm.

Python prototype (for reference only):

create([, initSampleCount[, initSeedCount[, pointDistribution]]]) -> retval

@spec create([{number(), number()}], [integer()]) :: t() | {:error, String.t()}

@spec create([{number(), number()}], integer()) :: t() | {:error, String.t()}

Variant 1:

Creates PCTSignatures algorithm using pre-generated sampling points and clusterization seeds indexes.

Positional Arguments

• initSamplingPoints: [Point2f].

  Sampling points used in image sampling.

• initClusterSeedIndexes: [int].

  Indexes of initial clusterization seeds. Its size must be lower or equal to initSamplingPoints.size().

Return

• retval: PCTSignatures

@return Created algorithm.

Python prototype (for reference only):

create(initSamplingPoints, initClusterSeedIndexes) -> retval

Variant 2:

Creates PCTSignatures algorithm using pre-generated sampling points and number of clusterization seeds. It uses the provided sampling points and generates its own clusterization seed indexes.

Positional Arguments

• initSamplingPoints: [Point2f].

  Sampling points used in image sampling.

• initSeedCount: int.

  Number of initial clusterization seeds. Must be lower or equal to initSamplingPoints.size().

Return

• retval: PCTSignatures

@return Created algorithm.

Python prototype (for reference only):

create(initSamplingPoints, initSeedCount) -> retval

@spec drawSignature(Evision.Mat.maybe_mat_in(), Evision.Mat.maybe_mat_in()) ::
  Evision.Mat.t() | {:error, String.t()}

Draws signature in the source image and outputs the result. Signatures are visualized as a circle with radius based on signature weight and color based on signature color. Contrast and entropy are not visualized.

Positional Arguments

• source: Evision.Mat.t().

  Source image.

• signature: Evision.Mat.t().

  Image signature.

Keyword Arguments

• radiusToShorterSideRatio: float.

  Determines maximal radius of signature in the output image.

• borderThickness: int.

  Border thickness of the visualized signature.

Return

• result: Evision.Mat.t().

  Output result.

Python prototype (for reference only):

drawSignature(source, signature[, result[, radiusToShorterSideRatio[, borderThickness]]]) -> result

@spec drawSignature(
  Evision.Mat.maybe_mat_in(),
  Evision.Mat.maybe_mat_in(),
  [{atom(), term()}, ...] | nil
) :: Evision.Mat.t() | {:error, String.t()}

Draws signature in the source image and outputs the result. Signatures are visualized as a circle with radius based on signature weight and color based on signature color. Contrast and entropy are not visualized.

Positional Arguments

• source: Evision.Mat.t().

  Source image.

• signature: Evision.Mat.t().

  Image signature.

Keyword Arguments

• radiusToShorterSideRatio: float.

  Determines maximal radius of signature in the output image.

• borderThickness: int.

  Border thickness of the visualized signature.

Return

• result: Evision.Mat.t().

  Output result.

Python prototype (for reference only):

drawSignature(source, signature[, result[, radiusToShorterSideRatio[, borderThickness]]]) -> result

@spec empty(t()) :: boolean() | {:error, String.t()}

Returns true if the Algorithm is empty (e.g. in the very beginning or after unsuccessful read

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: bool

Python prototype (for reference only):

empty() -> retval

@spec generateInitPoints([{number(), number()}], integer(), integer()) ::
  :ok | {:error, String.t()}

Generates initial sampling points according to selected point distribution.

Positional Arguments

• initPoints: [Point2f].

  Output vector where the generated points will be saved.

• count: int.

  Number of points to generate.

• pointDistribution: int.

  Point distribution selector. Available: UNIFORM, REGULAR, NORMAL.

Note: Generated coordinates are in range [0..1)

Python prototype (for reference only):

generateInitPoints(initPoints, count, pointDistribution) -> None

@spec getClusterMinSize(t()) :: integer() | {:error, String.t()}

This parameter multiplied by the index of iteration gives lower limit for cluster size. Clusters containing fewer points than specified by the limit have their centroid dismissed and points are reassigned.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: int

Python prototype (for reference only):

getClusterMinSize() -> retval

@spec getDefaultName(t()) :: binary() | {:error, String.t()}

getDefaultName

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: String

Returns the algorithm string identifier. This string is used as top level xml/yml node tag when the object is saved to a file or string.

Python prototype (for reference only):

getDefaultName() -> retval

@spec getDistanceFunction(t()) :: integer() | {:error, String.t()}

Distance function selector used for measuring distance between two points in k-means.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: int

Python prototype (for reference only):

getDistanceFunction() -> retval

@spec getDropThreshold(t()) :: number() | {:error, String.t()}

Remove centroids in k-means whose weight is lesser or equal to given threshold.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: float

Python prototype (for reference only):

getDropThreshold() -> retval

@spec getGrayscaleBits(t()) :: integer() | {:error, String.t()}

Color resolution of the greyscale bitmap represented in allocated bits (i.e., value 4 means that 16 shades of grey are used). The greyscale bitmap is used for computing contrast and entropy values.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: int

Python prototype (for reference only):

getGrayscaleBits() -> retval

@spec getInitSeedCount(t()) :: integer() | {:error, String.t()}

Number of initial seeds (initial number of clusters) for the k-means algorithm.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: int

Python prototype (for reference only):

getInitSeedCount() -> retval

@spec getInitSeedIndexes(t()) :: [integer()] | {:error, String.t()}

Initial seeds (initial number of clusters) for the k-means algorithm.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: [int]

Python prototype (for reference only):

getInitSeedIndexes() -> retval

@spec getIterationCount(t()) :: integer() | {:error, String.t()}

Number of iterations of the k-means clustering. We use fixed number of iterations, since the modified clustering is pruning clusters (not iteratively refining k clusters).

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: int

Python prototype (for reference only):

getIterationCount() -> retval

@spec getJoiningDistance(t()) :: number() | {:error, String.t()}

Threshold euclidean distance between two centroids. If two cluster centers are closer than this distance, one of the centroid is dismissed and points are reassigned.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: float

Python prototype (for reference only):

getJoiningDistance() -> retval

@spec getMaxClustersCount(t()) :: integer() | {:error, String.t()}

Maximal number of generated clusters. If the number is exceeded, the clusters are sorted by their weights and the smallest clusters are cropped.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: int

Python prototype (for reference only):

getMaxClustersCount() -> retval

@spec getSampleCount(t()) :: integer() | {:error, String.t()}

Number of initial samples taken from the image.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: int

Python prototype (for reference only):

getSampleCount() -> retval

@spec getSamplingPoints(t()) :: [{number(), number()}] | {:error, String.t()}

Initial samples taken from the image. These sampled features become the input for clustering.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: [Point2f]

Python prototype (for reference only):

getSamplingPoints() -> retval

@spec getWeightA(t()) :: number() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: float

Python prototype (for reference only):

getWeightA() -> retval

@spec getWeightB(t()) :: number() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: float

Python prototype (for reference only):

getWeightB() -> retval

@spec getWeightContrast(t()) :: number() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: float

Python prototype (for reference only):

getWeightContrast() -> retval

@spec getWeightEntropy(t()) :: number() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: float

Python prototype (for reference only):

getWeightEntropy() -> retval

@spec getWeightL(t()) :: number() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: float

Python prototype (for reference only):

getWeightL() -> retval

@spec getWeightX(t()) :: number() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: float

Python prototype (for reference only):

getWeightX() -> retval

@spec getWeightY(t()) :: number() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: float

Python prototype (for reference only):

getWeightY() -> retval

@spec getWindowRadius(t()) :: integer() | {:error, String.t()}

Size of the texture sampling window used to compute contrast and entropy (center of the window is always in the pixel selected by x,y coordinates of the corresponding feature sample).

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

Return

• retval: int

Python prototype (for reference only):

getWindowRadius() -> retval

@spec read(t(), Evision.FileNode.t()) :: t() | {:error, String.t()}

Reads algorithm parameters from a file storage

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• fn_: Evision.FileNode.t()

Python prototype (for reference only):

read(fn_) -> None

@spec save(t(), binary()) :: t() | {:error, String.t()}

save

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• filename: String

Saves the algorithm to a file. In order to make this method work, the derived class must implement Algorithm::write(FileStorage& fs).

Python prototype (for reference only):

save(filename) -> None

@spec setClusterMinSize(t(), integer()) :: t() | {:error, String.t()}

This parameter multiplied by the index of iteration gives lower limit for cluster size. Clusters containing fewer points than specified by the limit have their centroid dismissed and points are reassigned.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• clusterMinSize: int

Python prototype (for reference only):

setClusterMinSize(clusterMinSize) -> None

@spec setDistanceFunction(t(), integer()) :: t() | {:error, String.t()}

Distance function selector used for measuring distance between two points in k-means. Available: L0_25, L0_5, L1, L2, L2SQUARED, L5, L_INFINITY.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• distanceFunction: int

Python prototype (for reference only):

setDistanceFunction(distanceFunction) -> None

@spec setDropThreshold(t(), number()) :: t() | {:error, String.t()}

Remove centroids in k-means whose weight is lesser or equal to given threshold.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• dropThreshold: float

Python prototype (for reference only):

setDropThreshold(dropThreshold) -> None

@spec setGrayscaleBits(t(), integer()) :: t() | {:error, String.t()}

Color resolution of the greyscale bitmap represented in allocated bits (i.e., value 4 means that 16 shades of grey are used). The greyscale bitmap is used for computing contrast and entropy values.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• grayscaleBits: int

Python prototype (for reference only):

setGrayscaleBits(grayscaleBits) -> None

@spec setInitSeedIndexes(t(), [integer()]) :: t() | {:error, String.t()}

Initial seed indexes for the k-means algorithm.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• initSeedIndexes: [int]

Python prototype (for reference only):

setInitSeedIndexes(initSeedIndexes) -> None

@spec setIterationCount(t(), integer()) :: t() | {:error, String.t()}

Number of iterations of the k-means clustering. We use fixed number of iterations, since the modified clustering is pruning clusters (not iteratively refining k clusters).

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• iterationCount: int

Python prototype (for reference only):

setIterationCount(iterationCount) -> None

@spec setJoiningDistance(t(), number()) :: t() | {:error, String.t()}

Threshold euclidean distance between two centroids. If two cluster centers are closer than this distance, one of the centroid is dismissed and points are reassigned.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• joiningDistance: float

Python prototype (for reference only):

setJoiningDistance(joiningDistance) -> None

@spec setMaxClustersCount(t(), integer()) :: t() | {:error, String.t()}

Maximal number of generated clusters. If the number is exceeded, the clusters are sorted by their weights and the smallest clusters are cropped.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• maxClustersCount: int

Python prototype (for reference only):

setMaxClustersCount(maxClustersCount) -> None

@spec setSamplingPoints(t(), [{number(), number()}]) :: t() | {:error, String.t()}

Sets sampling points used to sample the input image.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

• samplingPoints: [Point2f].

  Vector of sampling points in range [0..1)

Note: Number of sampling points must be greater or equal to clusterization seed count.

Python prototype (for reference only):

setSamplingPoints(samplingPoints) -> None

@spec setTranslation(t(), integer(), number()) :: t() | {:error, String.t()}

Translations of the individual axes of the feature space.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

• idx: int.

  ID of the translation

• value: float.

  Value of the translation

Note:

   WEIGHT_IDX = 0;
   X_IDX = 1;
   Y_IDX = 2;
   L_IDX = 3;
   A_IDX = 4;
   B_IDX = 5;
   CONTRAST_IDX = 6;
   ENTROPY_IDX = 7;

Python prototype (for reference only):

setTranslation(idx, value) -> None

@spec setTranslations(t(), [number()]) :: t() | {:error, String.t()}

Translations of the individual axes of the feature space.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

• translations: [float].

  Values of all translations.

Note:

   WEIGHT_IDX = 0;
   X_IDX = 1;
   Y_IDX = 2;
   L_IDX = 3;
   A_IDX = 4;
   B_IDX = 5;
   CONTRAST_IDX = 6;
   ENTROPY_IDX = 7;

Python prototype (for reference only):

setTranslations(translations) -> None

@spec setWeight(t(), integer(), number()) :: t() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

• idx: int.

  ID of the weight

• value: float.

  Value of the weight

Note:

   WEIGHT_IDX = 0;
   X_IDX = 1;
   Y_IDX = 2;
   L_IDX = 3;
   A_IDX = 4;
   B_IDX = 5;
   CONTRAST_IDX = 6;
   ENTROPY_IDX = 7;

Python prototype (for reference only):

setWeight(idx, value) -> None

@spec setWeightA(t(), number()) :: t() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• weight: float

Python prototype (for reference only):

setWeightA(weight) -> None

@spec setWeightB(t(), number()) :: t() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• weight: float

Python prototype (for reference only):

setWeightB(weight) -> None

@spec setWeightContrast(t(), number()) :: t() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• weight: float

Python prototype (for reference only):

setWeightContrast(weight) -> None

@spec setWeightEntropy(t(), number()) :: t() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• weight: float

Python prototype (for reference only):

setWeightEntropy(weight) -> None

@spec setWeightL(t(), number()) :: t() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• weight: float

Python prototype (for reference only):

setWeightL(weight) -> None

@spec setWeights(t(), [number()]) :: t() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space.

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()

• weights: [float].

  Values of all weights.

Note:

   WEIGHT_IDX = 0;
   X_IDX = 1;
   Y_IDX = 2;
   L_IDX = 3;
   A_IDX = 4;
   B_IDX = 5;
   CONTRAST_IDX = 6;
   ENTROPY_IDX = 7;

Python prototype (for reference only):

setWeights(weights) -> None

@spec setWeightX(t(), number()) :: t() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• weight: float

Python prototype (for reference only):

setWeightX(weight) -> None

@spec setWeightY(t(), number()) :: t() | {:error, String.t()}

Weights (multiplicative constants) that linearly stretch individual axes of the feature space (x,y = position; L,a,b = color in CIE Lab space; c = contrast. e = entropy)

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• weight: float

Python prototype (for reference only):

setWeightY(weight) -> None

@spec setWindowRadius(t(), integer()) :: t() | {:error, String.t()}

Size of the texture sampling window used to compute contrast and entropy (center of the window is always in the pixel selected by x,y coordinates of the corresponding feature sample).

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• radius: int

Python prototype (for reference only):

setWindowRadius(radius) -> None

@spec write(t(), Evision.FileStorage.t()) :: t() | {:error, String.t()}

Stores algorithm parameters in a file storage

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• fs: Evision.FileStorage.t()

Python prototype (for reference only):

write(fs) -> None

@spec write(t(), Evision.FileStorage.t(), binary()) :: t() | {:error, String.t()}

write

Positional Arguments

• self: Evision.XFeatures2D.PCTSignatures.t()
• fs: Evision.FileStorage.t()
• name: String

Has overloading in C++

Python prototype (for reference only):

write(fs, name) -> None